2023 Day 14 Part 1

2023/day14.nim

@@ -0,0 +1,108 @@
+import std/algorithm
+import std/deques
+import std/enumerate
+import std/math
+import std/options
+import std/sequtils
+import std/sets
+import std/strscans
+import std/strutils
+import std/sugar
+import std/tables
+import std/terminal
+
+proc dbg[T](v: T): T = (echo(v); v)
+
+func empty[T](v: seq[T]): bool = v.len == 0
+
+proc split[T](v: seq[T], pred: proc(elt: T): bool): seq[seq[T]] =
+  var current: seq[T]
+  for elt in v:
+    if pred(elt):
+      result.add current
+      current = @[]
+    else:
+      current.add elt
+  result.add current
+
+func join[T](parts: seq[seq[T]], sep: T): seq[T] =
+  if parts.len > 0:
+    result &= parts[0]
+
+  for part in parts[1..^1]:
+    result.add sep
+    result &= part
+
+type Point = tuple
+  r: int
+  c: int
+
+type Platform = object
+  height: int
+  width: int
+
+  grid: Table[Point, char]
+
+  rows: seq[seq[char]]
+  cols: seq[seq[char]]
+
+func parsePlatform(text: string): Platform =
+  let lines = text.strip.splitLines()
+  result.height = lines.len
+  result.width = lines[0].len
+
+  for r in 0 ..< result.height:
+    result.rows.add @[]
+
+  for c in 0 ..< result.width:
+    result.cols.add @[]
+
+  for (r, line) in enumerate(lines):
+    for (c, sym) in enumerate(line):
+      result.grid[(r, c)] = sym
+      result.rows[r] &= @[sym]
+      result.cols[c] &= @[sym]
+
+proc fromCols(cols: seq[seq[char]]): Platform =
+  result.cols = cols
+  result.width = cols.len
+  result.height = cols[0].len
+
+  for r in 0 ..< result.height:
+    result.rows.add @[]
+
+  for (c, col) in enumerate(cols):
+    for (r, sym) in enumerate(col):
+      result.grid[(r, c)] = sym
+      result.rows[r] &= @[sym]
+
+func render(p: Platform): string =
+  p.rows.mapIt(it.mapIt($it).join("")).join("\n")
+
+proc tiltNorth(col: seq[char]): seq[char] =
+  let parts = col.split(func (sym: char): bool = sym == '#')
+  var rolled: seq[seq[char]]
+  for part in parts:
+    rolled.add part.sorted(Descending)
+  result = rolled.join('#')
+
+proc tiltNorth(p: Platform): Platform =
+  var cols: seq[seq[char]]
+  for col in p.cols:
+    cols.add col.tiltNorth
+  fromCols(cols)
+
+proc loadNorth(platform: Platform): int =
+  for (p, sym) in platform.grid.pairs:
+    if sym != 'O': continue
+    result.inc (platform.height - p.r)
+
+proc part1(input: string): int =
+  let text = readFile(input)
+  let platform = parsePlatform(text)
+  platform.tiltNorth.loadNorth
+
+echo part1("input/test.txt")
+echo part1("input/day14.txt")
+# echo part2("input/test.txt")
+# echo part2("input/day14.txt")